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Caffeine receptor

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https://www.readbyqxmd.com/read/28731505/calcium-calmodulin-dependent-kinase-2-camkii-mediates-epac-induced-spontaneous-transient-outward-currents-stocs-in-rat-vascular-smooth-muscle
#1
Edward S A Humphries, Tomoko Kamishima, John M Quayle, Caroline Dart
Activation of the major cAMP effector, exchange protein directly activated by cAMP (Epac), induces vascular smooth muscle relaxation by increasing the activity of ryanodine (RyR)-sensitive release channels on the peripheral sarcoplasmic reticulum. Resultant Ca(2+) sparks activate plasma membrane Ca(2+) -activated K(+) (BKCa ) channels, evoking spontaneous transient outward currents (STOCs) that hyperpolarize the cell and reduce voltage-dependent Ca(2+) entry. In this study we investigate the mechanism by which Epac increases STOC activity...
July 21, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28727921/effect-of-lysophosphatidylglycerol-on-intracellular-free-ca2-concentration-in-a10-vascular-smooth-muscle-cells
#2
Ying Zhang, Jing-Dian Zhang, Ming-Qin Zhu, Ming Zhang, Yan-Jun Xu, Li Cui, Naranjan S Dhalla
Although plasma levels of lysophosphatidylglycerol (LPG) are increased in hypertension, its role in the pathogenesis of vascular defects is not clear. In view of the importance of Ca2+-overload in causing vascular smooth muscle (VSM) dysfunction, the action of LPG on [Ca2+]i in cultured A10 VSM cell line was examined by using Fura 2-AM acetoxymethyl ester technique. LPG was found to induce a concentration-dependent increase in [Ca2+]i in VSM cells. This change was dependent both on the extracellular and intracellular Ca2+ sources as it was reduced by 30% by EGTA, an extracellular Ca2+ chelator, and 70% by tharpsigargin, a sarcoplasmic reticulum (SR) Ca2+-pump inhibitor...
July 20, 2017: Canadian Journal of Physiology and Pharmacology
https://www.readbyqxmd.com/read/28726639/mitochondrial-calcium-uniporter-in-drosophila-transfers-calcium-between-the-endoplasmic-reticulum-and-mitochondria-in-oxidative-stress-induced-cell-death
#3
Sekyu Choi, Xianglan Quan, Sunhoe Bang, Heesuk Yoo, Jiyoung Kim, Jiwon Park, Kyu-Sang Park, Jongkyeong Chung
Mitochondrial calcium plays critical roles in diverse cellular processes ranging from energy metabolism to cell death. Previous studies have demonstrated that mitochondrial calcium uptake is mainly mediated by the mitochondrial calcium uniporter (MCU) complex. However, the roles of the MCU complex in calcium transport, signaling, and dysregulation by oxidative stress still remain unclear. Here, we confirmed that Drosophila MCU contains evolutionarily conserved structures and requires essential MCU regulator (EMRE) for its calcium channel activities...
July 18, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28713161/functional-expression-of-the-ca-2-signaling-machinery-in-human-embryonic-stem-cells
#4
Ji-Jun Huang, Yi-Jie Wang, Min Zhang, Peng Zhang, He Liang, Hua-Jun Bai, Xiu-Jian Yu, Huang-Tian Yang
Emerging evidence suggests that Ca(2+) signals are important for the self-renewal and differentiation of human embryonic stem cells (hESCs). However, little is known about the physiological and pharmacological properties of the Ca(2+)-handling machinery in hESCs. In this study we used RT-PCR and Western blotting to analyze the expression profiles of genes encoding Ca(2+)-handling proteins; we also used confocal Ca(2+) imaging and pharmacological approaches to determine the contribution of the Ca(2+)-handling machinery to the regulation of Ca(2+) signaling in hESCs...
July 17, 2017: Acta Pharmacologica Sinica
https://www.readbyqxmd.com/read/28712806/structures-of-human-a1-and-a2a-adenosine-receptors-with-xanthines-reveal-determinants-of-selectivity
#5
Robert K Y Cheng, Elena Segala, Nathan Robertson, Francesca Deflorian, Andrew S Doré, James C Errey, Cédric Fiez-Vandal, Fiona H Marshall, Robert M Cooke
The adenosine A1 and A2A receptors belong to the purinergic family of G protein-coupled receptors, and regulate diverse functions of the cardiovascular, respiratory, renal, inflammation, and CNS. Xanthines such as caffeine and theophylline are weak, non-selective antagonists of adenosine receptors. Here we report the structure of a thermostabilized human A1 receptor at 3.3 Å resolution with PSB36, an A1-selective xanthine-based antagonist. This is compared with structures of the A2A receptor with PSB36 (2...
July 3, 2017: Structure
https://www.readbyqxmd.com/read/28696284/caffeine-induces-gastric-acid-secretion-via-bitter-taste-signaling-in-gastric-parietal-cells
#6
Kathrin Ingrid Liszt, Jakob Peter Ley, Barbara Lieder, Maik Behrens, Verena Stöger, Angelika Reiner, Christina Maria Hochkogler, Elke Köck, Alessandro Marchiori, Joachim Hans, Sabine Widder, Gerhard Krammer, Gareth John Sanger, Mark Manuel Somoza, Wolfgang Meyerhof, Veronika Somoza
Caffeine, generally known as a stimulant of gastric acid secretion (GAS), is a bitter-tasting compound that activates several taste type 2 bitter receptors (TAS2Rs). TAS2Rs are expressed in the mouth and in several extraoral sites, e.g., in the gastrointestinal tract, in which their functional role still needs to be clarified. We hypothesized that caffeine evokes effects on GAS by activation of oral and gastric TAS2Rs and demonstrate that caffeine, when administered encapsulated, stimulates GAS, whereas oral administration of a caffeine solution delays GAS in healthy human subjects...
July 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28675917/the-impact-of-coffee-on-health
#7
Karen Nieber
Coffee is one of the most popular and widely consumed beverages worldwide due to its stimulating effects on the central nervous system as well as its taste and aroma. Coffee is a complex mixture of more than 800 volatile compounds whereas caffeine and chlorogenic acids are the most common compounds. During the last years, coffee has progressively moved to a less negative position on health due to its better-known pharmacology. Caffeine, e.g., in a cup of coffee, appears to exert most of its effects through an antagonism of the adenosine receptors...
July 4, 2017: Planta Medica
https://www.readbyqxmd.com/read/28674254/caffeine-increases-hippocampal-sharp-waves-in-vitro
#8
Yusuke Watanabe, Yuji Ikegaya
Caffeine promotes memory consolidation. Memory consolidation is thought to depend at least in part on hippocampal sharp waves (SWs). In the present study, we investigated the effect of bath-application of caffeine in spontaneously occurring SWs in mouse acute hippocampal slices. Caffeine induced an about 100% increase in the event frequency of SWs at concentrations of 60 and 200 µM. The effect of caffeine was reversible after washout of caffeine and was mimicked by an adenosine A1 receptor antagonist, but not by an A2A receptor antagonist...
2017: Biological & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/28674253/effect-of-valerian-hop-mixture-on-sleep-related-behaviors-in-drosophila-melanogaster
#9
Hyeon-Son Choi, Bong Soo Ko, Hae Dun Kim, Ki-Bae Hong, Hyung Joo Suh
The aim of this study was to investigate the sleep-promoting effect of a Valerian/Hops mixture in fruit flies. The HPLC analysis showed that Valerenic acid (1260.53 µg/g of extract) and Xanthohumol (Cascade: 827.49 µg/g, Hallertau: 763.60 µg/g, Saaz: 186.93 µg/g) were contained in Valerian and Hop, respectively. The sleep patterns of fruit flies on the Valerian/Hops were examined in both baseline and caffeine-treated conditions. Total activities of flies significantly decreased in 20 mg/mL Valerian (74%), 10 mg/mL Cascade (25%), and 5 mg/mL Hallertau (11%) during nighttime or daytime compared with the control...
2017: Biological & Pharmaceutical Bulletin
https://www.readbyqxmd.com/read/28660093/the-taste-of-caffeine
#10
REVIEW
Rachel L Poole, Michael G Tordoff
Many people avidly consume foods and drinks containing caffeine, despite its bitter taste. Here, we review what is known about caffeine as a bitter taste stimulus. Topics include caffeine's action on the canonical bitter taste receptor pathway and caffeine's action on noncanonical receptor-dependent and -independent pathways in taste cells. Two conclusions are that (1) caffeine is a poor prototypical bitter taste stimulus because it acts on bitter taste receptor-independent pathways, and (2) caffeinated products most likely stimulate "taste" receptors in nongustatory cells...
June 1, 2017: Journal of Caffeine Research
https://www.readbyqxmd.com/read/28659466/caffeine-accelerates-recovery-from-general-anesthesia-via-multiple-pathways
#11
Robert Fong, Suhail Khokhar, Atif Newaz Chowdhury, Kelvin G Xie, Josiah Hiu-Yuen Wong, Aaron P Fox, Zheng Xie
Various studies have explored different ways to speed emergence from anesthesia. Previously, we have shown that three drugs that elevate intracellular cAMP (forskolin, theophylline and caffeine) accelerate emergence from anesthesia in rats. However, our earlier studies left two main questions unanswered. First, were cAMP elevating drugs effective at all anesthetic concentrations? Second, given that caffeine was the most effective of the drugs tested, why was caffeine more effective than forskolin since both drugs elevate cAMP? In our current study, emergence time from anesthesia was measured in adult rats exposed to 3% isoflurane for 60 minutes...
June 28, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28654087/caffeine-inhibits-hypothalamic-a1r-to-excite-oxytocin-neuron-and-ameliorate-dietary-obesity-in-mice
#12
Liufeng Wu, Jia Meng, Qing Shen, Yi Zhang, Susu Pan, Zhuo Chen, Ling-Qiang Zhu, Youming Lu, Yuan Huang, Guo Zhang
Caffeine, an antagonist of the adenosine receptor A1R, is used as a dietary supplement to reduce body weight, although the underlying mechanism is unclear. Here, we report that adenosine level in the cerebrospinal fluid, and hypothalamic expression of A1R, are increased in the diet-induced obesity (DIO) mouse. We find that mice with overexpression of A1R in the neurons of paraventricular nucleus (PVN) of the hypothalamus are hyperphagic, have glucose intolerance and high body weight. Central or peripheral administration of caffeine reduces the body weight of DIO mice by the suppression of appetite and increasing of energy expenditure...
June 27, 2017: Nature Communications
https://www.readbyqxmd.com/read/28646346/adenosine-and-sleep
#13
Michael Lazarus, Jiang-Fan Chen, Zhi-Li Huang, Yoshihiro Urade, Bertil B Fredholm
The classic endogenous somnogen adenosine promotes sleep via A1 and A2A receptors. In this chapter, we present an overview of the current knowledge regarding the regulation of adenosine levels, adenosine receptors, and available pharmacologic and genetic tools to manipulate the adenosine system. This is followed by a summary of current knowledge of the role of adenosine and its receptors in the regulation of sleep and wakefulness. Despite strong data implicating numerous brain areas, including the basal forebrain, the tuberomammillary nucleus, the lateral hypothalamus, and the nucleus accumbens, in the adenosinergic control of sleep, the complete neural circuitry in the brain involved in the sleep-promoting effects of adenosine remains unclear...
June 24, 2017: Handbook of Experimental Pharmacology
https://www.readbyqxmd.com/read/28643232/caffeine-protects-against-anticonvulsant-induced-neurotoxicity-in-the-developing-rat-brain
#14
Stefanie Endesfelder, Ulrike Weichelt, Cornelia Schiller, Marco Sifringer, Ivo Bendix, Christoph Bührer
Phenobarbital is the most commonly used drug for the treatment of neonatal seizures but may induce neurodegeneration in the developing brain. Methylxanthine caffeine is used for the treatment of apnea in newborn infants and appears to be neuroprotective, as shown by antiapoptotic and anti-inflammatory effects in oxidative stress models in newborn rodents and reduced rates of cerebral palsy in human infants treated with caffeine. We hypothesized that caffeine may counteract the proapoptotic effects of phenobarbital in newborn rats...
June 22, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/28611421/presence-of-caffeine-reversibly-interferes-with-efficacy-of-acupuncture-induced-analgesia
#15
Takumi Fujita, Changyong Feng, Takahiro Takano
Acupuncture is an alternative treatment for wide spectrum chronic pain. However, its validity remains controversial due to the disputed efficacy assessed in various clinical studies. Moreover, variability amongst individuals complicates the predictability of outcome, which impedes the integration of acupuncture into mainstream pain management programs. In light of our previous finding that the analgesic effect of acupuncture is mediated by adenosine A1 receptor activation at the acupuncture point, we here report that in acute and chronic animal pain models, oral intake of caffeine, a potent adenosine receptor antagonist, interferes with acupuncture analgesia, even at a low dose...
June 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28555252/the-perinatal-effects-of-maternal-caffeine-intake-on-fetal-and-neonatal-brain-levels-of-testosterone-estradiol-and-dihydrotestosterone-in-rats
#16
S Karaismailoglu, M Tuncer, S Bayrak, G Erdogan, E L Ergun, A Erdem
Testosterone, estradiol, and dihydrotestosterone are the main sex steroid hormones responsible for the organization and sexual differentiation of brain structures during early development. The hypothalamo-pituitary-adrenocortical axis, adrenal cells, and gonads play a key role in the production of sex steroids and express adenosine receptors. Caffeine is a non-selective adenosine antagonist; therefore, it can modulate metabolic pathways in these tissues. Besides, the proportion of pregnant women that consume caffeine is ∼60%...
August 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
https://www.readbyqxmd.com/read/28547666/effects-of-caffeine-intake-prior-to-stress-cardiac-magnetic-resonance-perfusion-imaging-on-regadenoson-versus-adenosine-induced-hyperemia-as-measured-by-t1-mapping
#17
R van Dijk, D Kuijpers, T A M Kaandorp, P R M van Dijkman, R Vliegenthart, P van der Harst, M Oudkerk
The antagonistic effects of caffeine on adenosine receptors are a possible cause of false-negative stress perfusion imaging. The purpose of this study was to determine the effects of coffee intake <4 h prior to stress perfusion cardiac magnetic resonance imaging (CMR) in regadenoson- versus adenosine-induced hyperemia as measured with T1-mapping. 98 consecutive patients with suspected coronary artery disease referred for either adenosine or regadenoson perfusion CMR were included in this analysis. Twenty-four patients reported coffee consumption <4 h before CMR (15 patients with adenosine, and 9 patients with regadenoson); 74 patients reported no coffee intake (50 patients with adenosine, and 24 patients with regadenoson)...
May 25, 2017: International Journal of Cardiovascular Imaging
https://www.readbyqxmd.com/read/28546857/chloroquine-inhibits-ca-2-permeable-ion-channels-mediated-ca-2-signaling-in-primary-b-lymphocytes
#18
Yi-Fan Wu, Ping Zhao, Xi Luo, Jin-Chao Xu, Lu Xue, Qi Zhou, Mingrui Xiong, Jinhua Shen, Yong-Bo Peng, Meng-Fei Yu, Weiwei Chen, Liqun Ma, Qing-Hua Liu
BACKGROUND: Chloroquine, a bitter tastant, inhibits Ca(2+) signaling, resulting in suppression of B cell activation; however, the inhibitory mechanism remains unclear. RESULTS: In this study, thapsigargin (TG), but not caffeine, induced sustained intracellular Ca(2+) increases in mouse splenic primary B lymphocytes, which were markedly inhibited by chloroquine. Under Ca(2+)-free conditions, TG elicited transient Ca(2+) increases, which additionally elevated upon the restoration of 2 mM Ca(2+)...
2017: Cell & Bioscience
https://www.readbyqxmd.com/read/28530573/identification-of-a-key-umami-active-fraction-in-modernized-korean-soy-sauce-and-the-impact-thereof-on-bitter-masking
#19
Yiseul Kim, Eun-Young Kim, Hee Jin Son, Jai-Jung Lee, Yong-Ho Choi, Mee-Ra Rhyu
Food protein hydrolysates created by natural fermentation have been used for centuries as food flavorings. The aim of this study was to define the key umami-active fraction of modernized Korean soy sauce (mJGN) and the impact thereof on bitter-masking of human sensory and bitter-taste receptor-expressing cells. We found strong correlations between taste profiles of mJGN and a contained fraction (F05). The latter contained compounds of less than 500Da, and elicits a distinct umami taste. Both free amino acids and Glu-enriched oligopeptides are suggested to be crucial in terms of the effects of F05 on taste...
October 15, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28525714/characterization-of-bitter-compounds-via-modulation-of-proton-secretion-in-human-gastric-parietal-cells-in-culture
#20
Kathrin I Liszt, Joachim Hans, Jakob P Ley, Elke Köck, Veronika Somoza
Humans perceive bitterness via around 25 different bitter receptors. Therefore, the identification of antagonists remains a complex challenge. We previously demonstrated several bitter tasting compounds such as caffeine to induce acid secretion in the stomach and in a human gastric tumor cell line (HGT-1). Here, the results of a fluorescent-based in vitro assay using HGT-1 cells and a human sensory panel testing nine selected potential bitter modulators with or without the bitter compounds caffeine or theobromine, were compared...
May 19, 2017: Journal of Agricultural and Food Chemistry
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